The long-term risk of venous thromboembolism following bariatric surgery

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality following bariatric surgery. The exact duration and magnitude of post-surgery risk for VTE, however, is unclear. We analyzed a large administrative database to determine the long-term risk and predictors for VTE in patients undergoing bariatric surgery.

A private insurance claims database was used to identify 17,434 patients who underwent bariatric surgery. Longitudinal data were available for each patient for up to 12 months post-surgery. We used logistic regression to identify independent predictors for VTE events.

The incidence of VTE during the index surgical hospitalization was .88%. This cumulative rate rose to 2.17% at 1 month and 2.99% by 6 months post-surgery. Over 74% of VTE events occurred after discharge. Risk factors identified for VTE developing by 6 months post-surgery included male sex (odds ratio (OR) = 1.68; confidence limits (CL) = 1.37-2.07), age ≥ 55 years (OR = 2.18; CL = 1.56-3.03), smoking (OR = 1.86; CL = 1.06-3.27), and previous VTE (OR = 7.48; CL = 5.78-9.67). The laparoscopic adjustable gastric band was less likely to result in VTE compared to open or laparoscopic gastric bypass (OR = .31; CL = .13-.75).

The period of increased risk for VTE following bariatric surgery extends well beyond the initial hospital discharge and 30 days after surgery. The high frequency of VTE up to 6 months following bariatric surgery suggests that more aggressively extended prophylaxis should be considered in patients at higher risk for VTE.